Pressure Relief Device for a Gear Box

ABSTRACT

A pressure relief device for a gear box which is disposed in the gear box and comprises a body, a blocking member and a spring. The body is defined with a penetrating hole. The spring pushes the blocking member and makes it seal the penetrating hole. When the pressure rises since the temperature therein is risen, and when the gas pressure in the gear box is larger than the force of the spring, the gas can push the blocking member and compress the spring, and then discharge from the penetrating hole of the body, thus reducing the pressure and the temperature of the gear box.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a component for a transmission device, and more particularly to a pressure relief device for a gear box.

2. Description of the Prior Art

A conventional gear box usually comprises a housing in which a plurality of gears being engaged with each other are disposed, and such a gear box can be used as a vehicle transmission box, or a speed changing device for a rotary cutting mechanism. In order to make the gears perform rotation and engaging movement more smoothly, the lubricating oil, such as machine oil or gear oil, is provided on the gears. However, when performing high speed, or long time rotation and engaging movement, the gears will produce heat energy and oil gas due to friction, such that the gas temperature in the gear box will be risen and the gas will be expanded. When the gear box is an enclosed space, the pressure inside the gear box will continuously rise, and when the structural intensity of the gear box is unable to support the gas pressure, the gear box will be damaged, or even cracked.

Therefore, a gear box as shown in FIG. 1 is developed, which also comprises the housing A in which the plurality of gears B1, B2 and B3 being engaged with each other are disposed. The housing A is defined with a through hole C from which the gas in the gear box is discharged, so as to balance the pressure in the gear box.

Although the gas in the gear box can be discharged from the through hole, the through hole C is always in open condition, if an accident happens, the lubricating oil in the gear box will be discharged from the through hole C to the outside completely. As a result, the environment is polluted.

The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a pressure relief device for a gear box which utilizes a spring to push a blocking member and make it seal a penetrating hole, when gas pressure in the gear box is enough to compress the spring, the gas will be discharged from the penetrating hole, so as to reduce the pressure and temperature of the gear box. In addition, at ordinary times, the penetrating hole is in close condition, so as to prevent the lubricating oil from discharging from the gear box due to overturn of the gear box.

To achieve the objective of the present invention, the pressure relief device disposed in the gear box comprises a body, a blocking member and an elastic member. The body passes through the gear box and is defined with a penetrating hole which enables an inner part to communicate with an outer part of the gear box. The blocking member and the elastic member are disposed in the penetrating hole. The elastic member pushes the blocking member towards the gear box, so as to make the blocking member seal the penetrating hole.

By such arrangements, the gear box can keep in close condition at ordinary times, so as to prevent the lubricating oil from discharging from the gear box due to overturn of the gear box. When the temperature in the gear box rises due to the friction of the gears to make gas in the gear box expand, and when the gas pressure which continuously rises enough to compress the elastic member, the gas will push the blocking member and compress the elastic member, and then the gas will discharge from the penetrating hole of the body, thus reducing the pressure and temperature of the gear box.

The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative view showing a conventional gear box;

FIG. 2 is an illustrative view showing a pressure relief device being disposed in the gear box in accordance with the present invention;

FIG. 3 is an illustrative view showing the pressure relief device for a gear box in accordance with the present invention; and

FIG. 4 is an illustrative view showing the pressure relief device for a gear box in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 2 and 3, a pressure relief device for a gear box in accordance with the present invention is disposed in a through hole C of a housing A and comprises a body 10, a blocking member 20, an elastic member 30 and a sponge 40.

The body 10 is defined with a penetrating hole 11 and is pipe-shaped. One end of the body 10 is defined with outer threads 12, and the through hole C of the housing A is defined with inner threads to be threaded with the outer threads 12 of the body 10. The penetrating hole 11 of the body 10 enables an inner part to communicate with an outer part of the housing A. The penetrating hole 11 comprises three orderly connected portions, that is, an inlet portion 111, a ventilating portion 112 and an outlet portion 113. The inlet portion 111 is in communication with the inner part of the housing A, and the outlet portion 113 is in communication with the outer part of the housing A. The caliber of the inlet portion 111 is smaller than that of the ventilating portion 112, and the caliber of the outlet portion 113 is also smaller than that of the ventilating portion 112. The other end of the body 10 is provided with a funnel structure 13 having a contracting end 131 with a smaller caliber and an expanding end 132 with a larger caliber. The funnel structure 13 is connected to and is in communication with the outlet portion 113 of the penetrating hole 11 by the contracting end 131.

The blocking member 20 is ball-shaped and is disposed in the ventilating portion 112 of the penetrating hole 11 of the body 10. The diameter of the blocking member 20 is larger than the caliber of the inlet portion 111.

One end of the elastic member 30 is pressed against the outlet portion 113 of the penetrating hole 11, and the other end of the elastic member 30 is pressed against the blocking member 20 in such a manner that the blocking member 20 will be pushed by the elastic member 30 to move towards the inlet portion 111 and provide a sealing effect between the inlet portion 111 of the penetrating hole 11 and the ventilating portion 112. The elastic member 30 in the present embodiment is a spring, and can also be an elastic piece or can be made by elastic material.

The sponge 40 is disposed in the funnel structure 13 of the body 10.

At ordinary times, the elastic member 30 pushes the blocking member 20 towards the inlet portion 111 of the penetrating hole 11 to seal the penetrating hole 11, so that even if the gear box is overturned, the lubricating oil in the gear box will not discharge from the penetrating hole 11, thus improving the security.

When gears B1, B2 and B3 in the gear box produce heat energy due to high speed, or long time rotation and engaging movement to rise the pressure of gas in the housing A since the temperature therein is risen, and when the gas pressure which rises enough to compress the elastic member 30 as shown in FIG. 4, the blocking member 20 is pushed and the elastic member 30 is compressed, such that the penetrating hole 11 will be in communication with the inner part of the housing A again. At this time, the gas in the housing A can be discharged from the penetrating hole 11, so as to reduce the pressure of the gear box. Moreover, the heat energy in the housing A will be discharged along with the gas, so that the air temperature in the housing A can also be reduced.

In addition, when the gear box is overturned under the condition that the penetrating hole 11 is in communication with the housing A, the sponge 40 disposed in the funnel structure 13 of the body 10 can also absorb the lubricating oil discharged from the penetrating hole 11, and the lubricating oil will flow into the gear box again by the guide of the funnel structure 13. When the gas discharges from the penetrating hole 11, the sponge 40 can also absorb the oil gas in the gas, further reducing the pollution and preventing the components from being contaminated by the oil gas.

While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. 

1. A pressure relief device for a gear box being disposed in the gear box, comprising: a body being passed through the gear box and defined with a penetrating hole, both ends of the penetrating hole being in communication with an inner part and an outer part of the gear box; a blocking member being disposed in the penetrating hole of the body; and an elastic member being disposed in the penetrating hole of the body and pushes the blocking member and makes it seal the penetrating hole, when gas pressure in the gear box which is enough to compress the elastic member, the gas will push the blocking member and compress the elastic member, and then will discharge from the penetrating hole of the body, thus relieving the pressure.
 2. The pressure relief device for a gear box as claimed in claim 1, wherein the penetrating hole of the body comprises three orderly connected portions, that is, an inlet portion, a ventilating portion and an outlet portion, the inlet portion is in communication with the inner part of the gear box, the outlet portion is in communication with the outer part of the gear box, and the blocking member and the elastic member are disposed in the ventilating portion of the penetrating hole of the body.
 3. The pressure relief device for a gear box as claimed in claim 2, wherein a caliber of the inlet portion is smaller than that of the ventilating portion, a caliber of the outlet portion is also smaller than that of the ventilating portion, the blocking member is ball-shaped, a diameter of the blocking member is larger than the caliber of the inlet portion, one end of the elastic member is pressed against the outlet portion of the penetrating hole, and the other end of the elastic member is pressed against the blocking member in such a manner that the blocking member will be pushed by the elastic member to move towards the inlet portion and provide a sealing effect between the inlet portion of the penetrating hole and the ventilating portion.
 4. The pressure relief device for a gear box as claimed in claim 2, wherein the body is provided with a funnel structure having a contracting end with a smaller caliber and an expanding end with a larger caliber, and the funnel structure is connected to and is in communication with the outlet portion of the penetrating hole by the contracting end.
 5. The pressure relief device for a gear box as claimed in claim 4, wherein a sponge is disposed in the funnel structure.
 6. The pressure relief device for a gear box as claimed in claim 1, wherein the elastic member is a spring. 